This paper presents two computer vision algorithms which address complementary aspects of the mobile robot navigation problem. The rst is a beacon system which allows for reliable and accurate robot localization, the second is a novel simple, but highly eeective, algorithm for colour based classiication which is used for reactive control. Two reactive control algorithms are built using the clas...

The primary issues concern whether objects have colours, and what sorts of properties the colours are. Some philosophers hold that nothing is coloured, others that colour are powers to affect perceivers, and others that colours are physical properties.

Colour vision and colour signals are important to aquatic animals, but light scattering and absorption by water distorts spectral stimuli. To investigate the performance of colour vision in water, and to suggest how photoreceptor spectral sensitivities and body colours might evolve for visual communication, we model the effects of changes in viewing distance and depth on the appearance of fish ...

Members of the bill¢sh family are highly visual predatory teleosts inhabiting the open ocean. Little is known about their visual abilities in detail, but past studies have indicated that these ¢shes were likely to be monochromats. This study, however, presents evidence of two anatomically distinct cone types in bill¢sh. The cells are arranged in a regular mosaic pattern of single and twin cones...

Alleles causing colour-blindness are present in humans at non-negligible levels, and it is not yet understood how colour-blindness is maintained, since colour-vision probably provides a selective advantage, e.g. when foraging. We show that after dark-adaptation colour-blinds had lower light perception thresholds than colour-normals (0.44 log-units), which may give a selective advantage under sc...

During the last decade it has become clear that colour vision in platyrrhines (New World monkeys) differs from the uniform trichromatic pattern normally found in catarrhines (Old World monkeys, apes and human). Colour vision in most platyrrhine species is polymorphic, with many dichromatic individuals. The comparison of response properties in retinal ganglion cells and lateral geniculate cells ...

While contrast normalization is well known to occur in luminance vision between overlaid achromatic contrasts, and in colour vision between overlaid colour contrasts, it is unknown whether it transfers between colour and luminance contrast. Here we investigate whether contrast detection in colour vision can be normalized by achromatic contrast, or whether this is a selective process driven only...